1. Field of the Invention
Embodiments of the invention relate to an optical semiconductor illuminating apparatus, and more particularly, to an optical semiconductor illuminating apparatus which permits various types of interconnection through a single module according to country and is capable of improving heat dissipation capabilities.
2. Discussion of the Background
Optical semiconductor devices such as light emitting diodes (LEDs) or laser diodes (LD) have attracted increasing attention due to advantages such as low power consumption, long lifespan, high durability, and excellent brightness, as compared with incandescent lamps or fluorescent lamps.
In addition, an illuminating apparatus based on such an optical semiconductor does not employ environmentally harmful materials such as mercury and is thus environmentally friendly.
In the related art, an optical semiconductor illuminating apparatus includes a plurality of light emitting modules to be suited for illuminating devices, such as street lamps, security lamps, and factory lamps, which are required to have high light output.
In such an optical semiconductor-based illuminating apparatus, each of the light emitting modules includes a light emitting section which emits light via operation of an LED, and a heat sink cooling the light emitting section and composed of a heat dissipating base and a plurality of heat dissipating fins.
The light emitting section is placed on one side of the heat dissipating base, and the plurality of heat dissipating fins are integrally formed at the other side thereof.
An illuminating apparatus employing such an optical semiconductor device as a light source generates large amounts of heat during operation of the light emitting modules which include optical semiconductor devices.
In addition, since the heat dissipating fins are formed only on a lower inner surface of the heat dissipating base, air flow passages between the heat dissipating fins are blocked by the heat dissipating base, thereby causing significant deterioration in heat dissipating efficiency of the light emitting module and the optical semiconductor illuminating apparatus including the same.
Although attempts have been made to secure air flow between the light emitting section and spaces between the heat dissipating fins by arranging the light emitting modules in a line to be separated from each other, this structure increases the volume of the illuminating apparatus, thereby making it difficult to obtain a compact structure, and causes an undesirable increase in distance between the light emitting sections, thereby deteriorating uniformity of illumination.
Moreover, this structure still provides a long passage for cold air to reach the heat dissipating fins, thereby providing a limited effect in improvement of heat dissipation efficiency.
Further, a conventional light emitting module has an external structure which cannot be applied to other illuminating apparatuses, and can be restrictively used only for associated illuminating apparatuses due to the absence of a drive circuit.
In recent years, although technology of integrating the drive circuit into the light emitting module has been suggested for the purpose of eliminating a switching mode power supply (SMPS), this technology has not been developed for general light emitting modules, and generalized light emitting modules are difficult to realize using only existing technologies known in the art.
Further, in such an illuminating apparatus, at least one light emitting module including a heat sink is assembled with a housing structure.
In the light emitting module, a printed circuit board (PCB) is placed on a front side of a heat sink having a plurality of heat dissipating fins formed on a rear side thereof, and light emitting devices each including an optical semiconductor are placed on the PCB.
However, the illuminating apparatus including such a light emitting module has a problem in that adaptations required to meet varying regulations between countries are difficult to realize.
Moreover, such an illuminating apparatus requires a predetermined heat transfer area to secure a certain degree of heat dissipation, thereby causing increase in volume and weight of the heat sink including the heat dissipating fins.